Not all fats are created equal, and work by AgResearch is
looking into how this knowledge can help reduce lamb deaths.

In good conditions, mortality of twins and triplets is below
10% and 20% respectively, but in poor weather conditions it
can be much more.

Many of these deaths occur in the first three days of life,
often because the lamb is unable to generate enough body heat
to keep warm during periods of extreme weather.

Immediately after birth and until they get a feed, lambs have
only one main way to regulate and maintain their body
temperature: burn ''brown fat'' to generate heat.

This special fat, officially called brown adipose tissue, is
vital for newborn lambs to generate enough heat to survive
extreme weather conditions.

Previous work at AgResearch looking at the effects of various
maternal supplements on lamb birth-weight and growth
performance also saw an increase in brown fat stores.

Research physiologist Dr Sue McCoard, from AgResearch's
Grasslands campus in Palmerston North wanted to look more
closely at this effect, as well as finding better ways of
measuring brown fat stores in animals.

She received a $35,000 Curiosity Fund grant, which is a seed
fund enabling AgResearch staff to investigate ideas that
could benefit the pastoral sector.

Her project has been looking at using thermal-imaging as the
first non-invasive way to measure the amount of brown fat in
the body, and what could possibly increase brown fat deposit
in multiple newborns.

''For the first few days of life, newborn lambs are reliant
on the brown fat.

''This is particularly important if they are born in
challenging circumstances such as storms, where chill index
is high, or if they don't have much milk to drink,'' Dr
McCoard said.

''Thermo-imaging is being looked at as a non-invasive way to
gauge the amount and availability of brown fat carried by
each animal.

''Previous to this, the only way to measure brown fat in the
body required the slaughter of animals.''

Increasing prolificacy in sheep is a cost-effective approach
to increase the efficiency of meat production in a
sustainable manner.

An increase in multiple pregnancies is one of the reasons
lamb production in New Zealand has been maintained despite
reductions in the number of breeding ewes in the past 20
years.

However, twins and triplets are usually smaller at birth and
suffer increased mortality early in life compared to their
singleton counterparts.

''It's a major issue on-farm, particularly where ewes haven't
been allocated enough feed, in times of cold stress,'' Dr
McCoard said.

''Finding consistent ways to increasing brown fat in newborn
lambs is key to improving core temperature, and therefore
survivability in early life.

''Increased lamb survival, and increasing the number of live
lambs that can be sold or used as replacements, will make a
major contribution to the welfare and economic outcomes of
lamb production on New Zealand sheep farms,'' she said.